Field flow fractionation devices involve particle size separation using a single inlet stream. See, e.g., Giddings, J. C., U.S. Pat. No. 3,449,938, Jun. 17, 1969, "Method for Separating and Detecting Fluid Materials"; Giddings, J. C., U.S. Pat. No. 4,147,621, Apr. 3, 1979, "Method and Apparatus for Field-Flow Fractionation"; Giddings, J. C., U.S. Pat. No. 4,214,981, Jul. 29, 1980, "Steric Field-Flow Fractionation"; Giddings, J. C. et al., U.S. Pat. No. 4,250,026, Feb. 10, 1981, "Continuous Steric FFF Device for The Size Separation of Particles"; Giddings, J. C. et al. (1983), "Outlet Stream Splitting for Sample Concentration in Field-Flow Fractionation," Separation Science and Technology 18:293-306; Giddings, J. C. (1985), "Optimized Field-Flow Fractionation System Based on Dual Stream Splitters," Anal. Chem. 57:945-947; Giddings, J. C., U.S. Pat. No. 4,830,756, May 16, 1989, "High Speed Separation of Ultra-High Molecular Weight Polymers by Hyperlayer Field-Flow Fractionation"; Giddings, J. C., U.S. Pat. No. 4,141,651, Aug. 25, 1992, "Pinched Channel Inlet System for Reduced Relaxation Effects and Stopless Flow Injection in Field-Flow Fractionation"; Giddings, J. C., U.S. Pat. No. 5,156,039, Oct. 20, 1992, "Procedure for Determining the Size and Size Distribution of Particles Using Sedimentation Field-Flow Fractionation"; Giddings, J. C., U.S. Pat. No. 5,193,688, Mar. 16, 1993, "Method and Apparatus for Hydrodynamic Relaxation and Sample Concentration in Field-Flow Fraction Using Permeable Wall Elements"; Caldwell, K. D. et al., U.S. Pat. No. 5,240,618, Aug. 31, 1993, "Electrical Field-Flow Fractionation Using Redox Couple Added to Carrier Fluid"; Giddings, J. C. (1993), "Field-Flow Fractionation: Analysis of Macromolecular, Colloidal and Particulate Materials," Science 260:1456-1465; Wada, Y. et al., U.S. Pat. No. 5,465,849, Nov. 14, 1995, "Column and Method for Separating Particles in Accordance with Their Magnetic Susceptibility"; Yve, V. et al. (1994), "Miniature Field-Flow Fractionation Systems for Analysis of Blood Cells," Clin. Chem. 40:1810-1814; Afromowitz, M. A. and Samaras, J. E. (1989), "Pinch Field Flow Fractionation Using Flow Injection Techniques," Separation Science and Technology 24(5 and 6):325-339.
Thin-channel split flow fractionation (SPLITT) technology also provides particle separation in a separation cell having a thin channel. A field force is exerted in a direction perpendicular to the flow direction. Particles travel from a particle-containing stream across a transport stream to a particle-free stream. The device for operating the process is generally fabricated from glass plates with teflon sheets used as spacers to form the channels. The channel depth can therefore be no smaller than the spacers, which are generally about 100 to 120 .mu.m thick. See, e.g., Giddings, J. C., U.S. Pat. No. 4,737,268, Apr. 12, 1988, "Thin Channel Split Flow Continuous Equilibrium Process and Apparatus for Particle Fractionation"; Giddings, J. C., U.S. Pat. No. 4,894,146, Jan. 16, 1990, "Thin Channel Split Flow Process and Apparatus for Particle Fractionation"; Giddings, J. C., U.S. Pat. No. 5,093,426, Aug. 13, 1991, "Process for Continuous Particle and Polymer Separation in Split-Flow Thin Cells Using Flow-Dependent Lift Forces"; Williams, P. S. et al. (1992), "Continuous SPLITT Fractionation Based on a Diffusion Mechanism," Ind. Eng. Chem. Res. 31:2172-2181; and Levin, S. and Tawil, G. (1993), "Analytical SPLITT Fractionation in the Diffusion Mode Operating as a Dialysis-like System Devoid of Membrane. Application to Drug-Carrying Liposomes, " Anal. Chem. 65:2254-2261.
The object of this invention is to provide an improved extraction system utilizing differential transport principles in which the analyte can be extracted, detected and quantified. A further object of this invention is to provide an improved extraction system for purification and treatment of fluids, including bodily fluids such as blood.
All publications, patents and patent applications referred to herein are incorporated in their entirety by reference.